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2.
Amino Acids ; 36(1): 13-9, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18188665

RESUMO

The brain protein synthesis is sensitive to the dietary protein; however, the role of dietary protein on biomarkers including choline acetyltransferase and nerve growth factor (NGF) for the function of cholinergic neurons remains unknown in young rats. The purpose of this study was to determine whether the quantity and quality of dietary protein affects the concentration of NGF and activity of choline acetyltransferase, and their mRNA levels in the brains of young rats. Experiments were carried out on five groups of young rats (4 weeks) given the diets containing 0, 5, 20% casein, 20% gluten or 20% gelatin for 10 days. The activity of choline acetyltransferase in the cerebral cortex and hippocampus declined gradually with a decrease in quantity and quality of dietary protein. The concentration of NGF in the cerebral cortex and the mRNA levels of choline acetyltransferase in the cerebral cortex and hippocampus did not differ among groups. However, the concentration and mRNA level of NGF in the hippocampus was significantly lower in rats fed with lower quantity of protein or lower quality of protein. In the hippocampus, the mRNA levels of NGF significantly correlated with the NGF concentration when the quantity (r = 0.704, P < 0.01) and quality (r = 0.682, P < 0.01) of dietary protein was manipulated. It was further found that a significant positive correlation existed between the NGF concentration and the activity of choline acetyltransferase in the hippocampus (dietary protein quantity, r = 0.632, P < 0.05; dietary protein quality, r = 0.623, P < 0.05). These results suggest that the ingestion of lower quantity and quality of dietary protein are likely to control the mRNA level and concentration of NGF, and cause a decline in the activity of choline acetyltransferase in the brains of young rats.


Assuntos
Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Colina O-Acetiltransferase/metabolismo , Proteínas Alimentares/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Fatores de Crescimento Neural/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Colina O-Acetiltransferase/genética , Masculino , Fatores de Crescimento Neural/genética , Tamanho do Órgão/efeitos dos fármacos , RNA Mensageiro/genética , Ratos , Ratos Wistar
3.
Amino Acids ; 32(2): 247-53, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16755367

RESUMO

The purpose of the present study was to determine whether the regulation of brain protein synthesis was mediated through changes in the plasma concentrations of insulin and growth hormone (GH), and whether the concentrations of amino acids in the brain and plasma regulate the brain protein synthesis when the quantity and quality of dietary protein is manipulated. Two experiments were done on three groups of aged rats given diets containing 20% casein, 5% casein or 0% casein (Experiment 1), and 20% casein, 20% gluten, or 20% gelatin (Experiment 2) for 1 d (only one 5-h period) after all rats were fed the 20% casein diet for 10 d (only 5-h feeding per day). The aggregation of brain ribosomes, the concentration in plasma GH, and the branched chain amino acids in the plasma and cerebral cortex declined with a decrease of quantity and quality of dietary protein. The concentration of plasma insulin did not differ among groups. The results suggest that the ingestion of a higher quantity and quality of dietary protein increases the concentrations of GH and several amino acids in aged rats, and that the concentrations of GH and amino acids are at least partly related to the mechanism by which the dietary protein affects brain protein synthesis in aged rats.


Assuntos
Aminoácidos/química , Encéfalo/metabolismo , Hormônio do Crescimento/metabolismo , Proteínas/química , Envelhecimento , Aminoácidos/metabolismo , Animais , Córtex Cerebral/metabolismo , Proteínas Alimentares , Masculino , Modelos Biológicos , Polirribossomos/metabolismo , Biossíntese de Proteínas , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar
4.
Amino Acids ; 32(2): 255-60, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16755368

RESUMO

The purpose of this study was to determine whether the gamma-aminobutyric acid (GABA) affects the rate of brain protein synthesis in male rats. Two experiments were done on five or three groups of young rats (5 wk) given the diets containing 20% casein administrated 0 mg, 25 mg, 50 mg, 100 mg or 200 mg/100 g body weight GABA dissolved in saline by oral gavage for 1 day (d) (Experiment 1), and given the diets contained 0%, 0.25% or 0.5% GABA added to the 20% casein diet (Experiment 2) for 10 d. The plasma concentration of growth hormone (GH) was the highest in rats administrated 50 mg and 100 mg/100 g body weight GABA. The concentration of serum GABA increased significantly with the supplementation groups. The fractional (Ks) rates of protein synthesis in brain regions, liver and gastrocnemius muscle increased significantly with the 20% casein + 0.25% GABA diet and still more 20% casein + 0.5% GABA compared with the 20% casein diet. In brain regions, liver and gastrocnemius muscle, the RNA activity [g protein synthesized/(g RNA . d)] significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. Our results suggest that the treatment of GABA to young male rats are likely to increase the concentrations of plasma GH and the rate of protein synthesis in the brain, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis.


Assuntos
Ração Animal , Encéfalo/metabolismo , Biossíntese de Proteínas/efeitos dos fármacos , Ácido gama-Aminobutírico/administração & dosagem , Envelhecimento , Animais , Peso Corporal , Química Encefálica , Proteínas Alimentares/metabolismo , Hormônio do Crescimento/metabolismo , Masculino , RNA/metabolismo , Ratos , Ratos Wistar , Distribuição Tecidual
5.
Interv Neuroradiol ; 12(Suppl 1): 129-32, 2006 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-20569617

RESUMO

SUMMARY: To diagnose VA dissection, MRA or cerebral angiography, which provides information regarding intra-vascular space, has been performed. We report the acquisition of various information about VA dissection using MRI-BPAS, which is a new diagnostic method.

6.
Interv Neuroradiol ; 12(Suppl 1): 201-4, 2006 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-20569632

RESUMO

SUMMARY: Contralateral carotid artery occlusion is thought to represent a significant risk factor in carotid endarterectomy (CEA). There is also evidence that intraoperative and postoperative hypotention may cause contralateral hemodynamic ischemia. As such, contralateral carotid artery occlusion is regarded as a risk factor for carotid angioplasty and stenting (CAS). In this paper, we report on five cases of severe ICA stenosis with contralateral carotid artery occlusions. Cerebral blood flow(CBF) and cerebral vasoreactivity( CVR) of the contralateral carotid artery occlusions were measured before and after CAS. Additionally, the influence that ipsilateral CAS exerted on the occluded side was examined. (123)I-IMP SPECT was performed before and after CAS, both at rest and at the time of acetazoramide administration. The CBF was evaluated quantitatively using the ARG method. The mean CBF of the treated side rose from 30.0 +/- 7.1 ml/100g/min to 34.4 +/- 8.3 ml/100g/min (p < 0.05), and the mean CBF of the occluded side similarly rose from 28.3 +/- 6.1 ml/100g/min to 31.7 +/- 6.4 ml/100g/min (p < 0.05). Correspondingly, the regional CVR (rCVR) increased from 5.9% +/- 16.3% to 35.0% +/- 16.4%(p < 0.05) on the treated side, and from 3.7% +/- 14.7% to 10.7% +/- 16.9% (p < 0.05) on the occluded side. This demonstrates that ipsilateral CAS seems to improve both CBF and CVR on the contralateral occluded side. The fact that some cases developed cross flow from the anterior communicating artery was both remarkable and significant. Where there was poor cross flow from the anterior communicating artery, improvement in cerebral vaso reactivity was limited.

7.
Amino Acids ; 28(3): 297-303, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15789139

RESUMO

We have shown that urinary urea excretion increased in rats fed a low quality protein. The purpose of present study was to determine whether an addition of dietary limiting amino acids affected urea synthesis in rats fed a low gluten diet. Experiments were done on three groups of rats given diets containing 10% gluten, 10% gluten +0.5% L-lysine or 10% gluten+0.5% L-lysine, 0.2% L-threonine and 0.2% L-methionine for 10 d. The urinary excretion of urea, and the liver concentrations of serine and ornithine decreased with the addition of dietary L-lysine, L-threonine and L-methionine. The fractional and absolute rates of protein synthesis in tissues increased with the treatment of limiting amino acids. The activities of hepatic urea-cycle enzymes was not related to the urea excretion. These results suggest that the addition of limiting amino acids for the low gluten diet controls the protein synthesis in tissues and hepatic ornithine and decline urea synthesis.


Assuntos
Dieta , Glutens/administração & dosagem , Lisina/administração & dosagem , Metionina/administração & dosagem , Treonina/administração & dosagem , Ureia/urina , Animais , Suplementos Nutricionais , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar
8.
Life Sci ; 69(12): 1419-27, 2001 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-11531165

RESUMO

It is known that protein kinase C (PKC) activity may be one of the fundamental cellular changes associated with memory function. Apolipoprotein E (apoE) deficiency causes cholinergic deficits and memory impairment. ApoE-deficient mouse has been employed as a serviceable model for studying the relation between apoE and the memory deficit induced by cholinergic impairment. Brain-fatty acid binding protein (b-FABP) might be functional during development of the nervous system. Peroxisome proliferator-activated receptor (PPAR) is involved in the early change in lipid metabolism. We investigated the alterations not only in cerebral PKC activity, but also in the gene expressions of PKC-beta, brain-FABP and PPAR-alpha in apoE-deficient mice. The results showed that there was a lower cerebral membrane-bound PKC activity in the apoE-deficient mice than in its wild type strain (C57BL/6). But there were no significant differences in cytosolic PKC activity. PKC-beta, b-FABP and PPAR-alpha mRNA expressions in cerebrum were lowered in apoE-deficient mice. These findings may be involved in the dysfunction of the brain neurotransmission system in apoE-deficient mouse. Alternatively, these results also suggest that cerebral apoE plays an important role in brain PKC activation by maintaining an appropriate expression of b-FABP and PPAR-alpha mRNAs.


Assuntos
Doença de Alzheimer/enzimologia , Apolipoproteínas E/deficiência , Isoenzimas/metabolismo , Proteínas de Neoplasias , Proteínas do Tecido Nervoso , Proteína Quinase C/metabolismo , RNA Mensageiro/metabolismo , Telencéfalo/enzimologia , Doença de Alzheimer/etiologia , Animais , Apolipoproteínas E/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Primers do DNA/química , Modelos Animais de Doenças , Proteína 7 de Ligação a Ácidos Graxos , Proteínas de Ligação a Ácido Graxo , Isoenzimas/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Quinase C/genética , Proteína Quinase C beta , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
9.
J Nutr ; 131(1): 123-6, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11208948

RESUMO

The purpose of this study was to determine whether 17-ss-estradiol affects the rate of brain protein synthesis in ovariectomized female rats. Experiments were conducted on three groups of 12-wk-old female rats: group 1 were ovariectomized to reduce the level of plasma estradiol, group 2 were ovariectomized and treated with estradiol and group 3 were sham-operated controls. The fractional rates of protein synthesis in brain of ovariectomized rats treated with estradiol were significantly greater than that in ovariectomized rats without estradiol treatment. In the cerebral cortex and cerebellum, the RNA activity [g protein synthesized/(g RNA. d)] significantly correlated (r > 0.87, P < 0.001) with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that estrogen treatment of ovariectomized female rats is likely to increase the rate of protein synthesis in the brain and that RNA activity is at least in part related to the fractional rate of brain protein synthesis.


Assuntos
Encéfalo/metabolismo , Estradiol/farmacologia , Proteínas do Tecido Nervoso/biossíntese , Ovariectomia , Animais , Cerebelo/metabolismo , Córtex Cerebral/metabolismo , Feminino , RNA/metabolismo , Ratos , Ratos Wistar
10.
Interv Neuroradiol ; 7(Suppl 1): 137-42, 2001 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-20663391

RESUMO

SUMMARY: To examine the long term results of endovascular treatment of cerebral aneurysms with the Guglielmi detachable coil (GDC) system, follow- up (F/U) angiography was performed at 6, 12 and 24 months after the procedure. We analyzed 45 cases, 49 procedures of GDC treated cerebral aneurysms from 1997.6. to 2000.5. Follow- up angiography was achieved at 6M 43/45 (96%), 12M 29/33 (87%) and 24M 22/25 (88%). Angiographical changes were found 23/43 (53%) of the cases at 6M F/U. There were angiographical improvements in 12 cases (CP: complete occlusion, NR: neck remnant, PA: partial occlusion, PA-CP; 8, NR-CP; 1, PA-NR; 3) and angiographical worsening in 11 cases (CP-NR; 5, CP-PA; 3, PA-PA; 3) at 6M F/U. Two cases had been demonstrating progressive angiographical worsening at 6M and 12M F/U (CP-NR-PA). No angiographical change was found at 24M F/U. There was no case of hemorrhage or re-hemorrhage after GDC treatment. In cases of side-wall aneurysm, tight packing of the inflow side of the aneurysm and small neck aneurysm were thought to be causes of the angiographical improvements. In patients with wide neck aneurysms with partial occlusion result were angiographic worsening at the F/U. Other factors of angiographical worsening were improper working angle at the procedure and improper follow-up angle at the angiography and the intraluminal clot in the case of ruptured aneurysm.

12.
Biosci Biotechnol Biochem ; 64(7): 1466-71, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10945265

RESUMO

The purpose of this study was to find whether the addition of dietary lysine affected the rate of brain protein synthesis in aged rats fed on a gluten diet. Experiments were done on two groups of aged rats (30 wk) given the diets containing 5% gluten or 5% gluten + 0.3% lysine for 10 d. The fractional rates of protein synthesis in brain, liver, and kidney increased with an addition of dietary lysine. In brain, liver, and kidney, the RNA activity [g protein synthesized/(g RNA x d)] was significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that the addition of the limiting amino acid for the low quality protein elevates the rate of protein synthesis in the brain of aged rats, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis.


Assuntos
Envelhecimento/metabolismo , Encéfalo/metabolismo , Suplementos Nutricionais , Glutens/metabolismo , Lisina/metabolismo , Biossíntese de Proteínas , Animais , Peso Corporal , Masculino , RNA/metabolismo , Ratos , Ratos Wistar
13.
Interv Neuroradiol ; 6 Suppl 1: 227-31, 2000 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-20667254

RESUMO

SUMMARY: We summarize our clinical experience of the local fibrinolysis for the middle cerebral artery (MCA) embolism.We added residual CBF factors of the ischemic territories to the usual criteria for the indication of fibrinolysis by Xe-SPECT CBF measurement. Forty-nine cases of local fibrinolysis for MCA embolism were reviewed and the results were compared with the conservative medical treatment cases. Angiographical improvements were achieved in 38 cases (76%, full reopening 17/49, partial reopening 21/49) and favorable outcomes (good recovery at GOS) were obtained in 32 cases (65%) at three months follow-up outcome. In comparison with the conservative medical treatment, fibrinolysis was superior at good recovery rate, severe disability rate and the resulted large infarction rate with statistical significance. We concluded that the local fibrinolysis with evaluation of the residual CBF of the ischemic territories achieved good results and outcomes and superior to the conservative medical treatment at some points. To keep the therapeutic time window, it is necessary to include the CBF factor to the criteria for the indication of this treatment.

14.
J Nutr Sci Vitaminol (Tokyo) ; 45(4): 481-9, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10575638

RESUMO

The purpose of this study was to determine whether the quality of dietary protein affects the rate of brain protein synthesis in aged rats. Experiments were conducted on three groups of aged rats (30 wk) given diets containing 20 g casein, 20 g gluten or 20 g gelatin/100 g for 10 d. The fractional rates of protein synthesis in the brain, liver and kidney declined with the decrease in quality of dietary protein. In the brain, liver and kidney, the RNA activity [g protein synthesized/(g RNA.d)] correlated significantly with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that the rate of protein synthesis in the brain declines with the decrease in quality of dietary protein consumed by aged rats, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis.


Assuntos
Envelhecimento , Encéfalo/metabolismo , Proteínas Alimentares/administração & dosagem , Proteínas do Tecido Nervoso/biossíntese , Animais , Caseínas/administração & dosagem , Gelatina/administração & dosagem , Glutens/administração & dosagem , Rim/metabolismo , Fígado/metabolismo , Masculino , Tamanho do Órgão , Biossíntese de Proteínas , RNA/análise , RNA/metabolismo , Ratos , Ratos Wistar , Aumento de Peso
15.
Biosci Biotechnol Biochem ; 63(3): 506-9, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10227137

RESUMO

We determined whether the synthesis and degradation of N-acetylglutamate would regulate urea synthesis when the ornithine status was manipulated. Experiments were done on two groups of rats, each being treated with ornithine or saline (control). The plasma concentration of urea and the liver concentration of N-acetylglutamate in rats given ornithine were each significantly higher than in the control rats. Compared with the control rats, the liver N-acetylglutamate degradation was significantly lower in those rats treated with ornithine. Treatment of the rats with ornithine did not affect N-acetylglutamate synthesis in the liver. An inverse correlation between the liver N-acetylglutamate degradation and liver concentration of N-acetylglutamate was found. These results suggest that the lower degradation of N-acetylglutamate in the ornithine treatment group would be likely to increase the hepatic concentration of this compound and stimulate urea synthesis.


Assuntos
Glutamatos/biossíntese , Fígado/metabolismo , Ornitina/farmacologia , Animais , Peso Corporal , Dieta , Glutamatos/metabolismo , Meia-Vida , Fígado/efeitos dos fármacos , Masculino , Tamanho do Órgão , Ratos , Ratos Wistar , Ureia/sangue
16.
J Nutr ; 128(9): 1533-6, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9732315

RESUMO

The purpose of this study was to determine whether the quantity of dietary protein affects the rate of brain protein synthesis in aged rats. Experiments were conducted on three groups of 30-wk-old rats fed diets containing 0, 5 or 20 g casein/100 g for 10 d. The fractional rates of protein synthesis in brain, liver and kidney declined with a decrease in quantity of dietary protein. In brain, liver and kidney, RNA activity [g protein synthesized/(g RNA.d)] was significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that the rate of protein synthesis in the brain declines with a decrease in quantity of dietary protein in aged rats, and that RNA activity is at least partly related to the fractional rate of brain protein synthesis.


Assuntos
Envelhecimento/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Proteínas Alimentares/farmacologia , Biossíntese de Proteínas , Envelhecimento/metabolismo , Animais , Peso Corporal , Encéfalo/metabolismo , Caseínas/farmacologia , Proteínas Alimentares/administração & dosagem , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Tamanho do Órgão , Ratos , Ratos Wistar
17.
Biosci Biotechnol Biochem ; 62(3): 535-9, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9571783

RESUMO

We determined whether the synthesis and degradation of N-acetylglutamate would regulate urea synthesis when the thyroid status was manipulated. Experiments were done on three groups of rats, each being given 6-propyl-2-thiouracil (PTU, a thyroid inhibitor) without a triiodothyronine (T3) treatment, treated with PTU + T3, or receiving neither PTU nor T3 (control). The plasma concentration and urinary excretion of urea, the liver concentration of N-acetylglutamate, and the liver N-acetylglutamate synthesis in rats given PTU alone were each significantly higher than in the control rats. Compared with the control rats, the liver N-acetylglutamate degradation was significantly lower in those rats given PTU without the T3 treatment. Treatment of the PTU-treated rats with T3 reversed the effects of PTU to the values of the control rats. N-Acetylglutamate synthesis in the liver was closely correlated with the excretion of urea, and inverse correlation between the liver N-acetylglutamate degradation and urea excretion was found. These results suggest that the greater synthesis and lower degradation of N-acetylglutamate in the hypothyroid (PTU alone) rats would be likely to increase the hepatic concentration of this compound and stimulate urea synthesis.


Assuntos
Glutamatos/metabolismo , Tri-Iodotironina/farmacologia , Ureia/metabolismo , Animais , Glutamatos/biossíntese , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Propiltiouracila/farmacologia , Ratos , Ratos Wistar , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/fisiologia , Ureia/sangue , Ureia/urina
18.
Interv Neuroradiol ; 4 Suppl 1: 23-5, 1998 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-20673435

RESUMO

SUMMARY: We summarized our clinical experience of thrombolytic therapy for cerebral embolism to evaluate the relation between the prognosis and the occlusion site, and the role of pre-treatment CBF measurement for supratentorial cerebral embolism. 56 cases of thrombolysis were analyzed and results were compaired with conservative medical therapy group. For ICA embolism, we stopped thrombolysis in the early period because of its poor collateral circulation. MCA embolism seemed to be a good candidate for this treatment and results were significantly better than the conservative medical therapy group in good recovery rate, severe disablity rate and large size infarction rate. In basilar artery embolism, thrombolysis seemed to be the most effective treatment in spite of the high mortality rate. Pre-treatment CBF measurement was important and useful to estimate the severity of ischemia, and it could make it possible to avoid severe hemorrhagic complications.

19.
Biosci Biotechnol Biochem ; 61(9): 1536-40, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9339556

RESUMO

The effect of the thyroid hormone on the rate of brain protein synthesis in rats was studied. Experiments were conducted on three groups of rats given 6-propyl-2-thiouracil (PTU, a thyroid inhibitor) without a triiodothyronine (T3) treatment, those treated with PTU + T3, and those treated with neither PTU nor T3 (control). The fractional rates of protein synthesis in the brain, liver, and kidney of rats given PTU + T3 were significantly greater than those in rats given PTU alone. In the brain and kidney, the RNA activity [g of protein synthesized/(g of RNA.d)] were significantly correlated with the fractional rates of protein synthesis. In the liver and kidney, the RNA concentration (mg of RNA/g of protein) was related to the fractional rate of protein synthesis. These results suggest that the thyroid hormone treatment would be likely to increase the rate of protein synthesis in the brain of rats, and that the RNA activity is, at least partly, related to the fractional rate of brain protein synthesis.


Assuntos
Química Encefálica/efeitos dos fármacos , Proteínas do Tecido Nervoso/biossíntese , Hormônios Tireóideos/farmacologia , Animais , Antitireóideos/farmacologia , Dieta , Cinética , Masculino , Tamanho do Órgão/efeitos dos fármacos , Fenilalanina/sangue , Propiltiouracila/farmacologia , RNA/biossíntese , Ratos , Ratos Wistar , Aumento de Peso/efeitos dos fármacos
20.
J Nutr Sci Vitaminol (Tokyo) ; 43(3): 387-96, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9268926

RESUMO

The purpose of this study was to find whether or not the ornithine transport into mitochondria regulated urea synthesis when the thyroid status is manipulated. Experiments were done on three groups of rats: given 6-propyl-2-thiouracil (PTU, a thyroid inhibitor) without triiodothyronine (T3) treatment, treated with PTU+T3 or receiving neither PTU nor T3 (control). The urinary excretion of urea, liver concentration of ornithine and ornithine transport into isolated hepatic mitochondria in rats given PTU+T3 were significantly lower than in rats given PTU alone. Ornithine transport was significantly inhibited by the addition of lysine specifically. This response was achieved well within the physiological concentration of lysine. Compared with rats given PTU without T3 treatment, the liver concentration of lysine was significantly higher in rats treated with PTU+T3 and control rats. Ornithine transport into hepatic mitochondria was closely correlated with the excretion of urea. The results suggest that the greater ornithine transport in the hypothyroid (PTU alone) rats is likely to stimulate urea synthesis. A thyroid hormone-induced increase in lysine concentration may be at least partly responsible for the changes in ornithine transport into mitochondria.


Assuntos
Mitocôndrias Hepáticas/efeitos dos fármacos , Ornitina/metabolismo , Tri-Iodotironina/farmacologia , Ureia/metabolismo , Animais , Transporte Biológico , Lisina/farmacologia , Masculino , Mitocôndrias Hepáticas/metabolismo , Ratos , Ratos Wistar , Ureia/sangue , Ureia/urina
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